Hydraulic remote control apparatus



March'zo, 1945. AMERY IHYDRAULICQREMOTE CONTROLAPPARATU'S -2 Sheets-Shet 1 Filed April 19, 1943 March 20, 1945. G AMERY A 2,371,596

HYDRAULIC REMOTE CONTROL APPARATUS Filed April 19, 194s 2 sheets-sheet 2' Patent ed Mar. 20, 1945 HYDRAULIC REMOTE CONTROL APPARATUS I George Amery, Harborne, Birmingham, England; Marjorie Amery administratrix of said George Amery, deceased Application April 19, 1943, Serial No. 483,653

In Great Britain December 31, 1941 3 Claims.

This invention comprises improvements in or relating to hydraulic remote control apparatus; It is an object of the invention to provide means whereby movements of an actuator at a transmit ting station produce corresponding movements of 5 vices on aircraft such as throttles or the opening an actuated member at a receiving station and of doors, the release of projectiles, the operation in which reaction of the actuated member on the of flaps and rudders and the like. The irreversiactuator is reduced or minimised. ole feature of the control makes the apparatus -It is known to transmit movement by means particularly useful for operating. rudders and of hydraulic remote control apparatus comprising, flaps, or for operating'brakes on wheels. In the at a transmitting station, an actuator and pistonlatter case fatigue is obviated as the brake will and-cylinder mechanism operated by the actuator remain on at a predetermined pressure until the to impel hydraulic liquid, corresponding-pistonoperator completely releases the brake pedal, and-cylinder mechanism at a receiving station to without the necessity of maintaining fullpressure be actuated by said liquid and conduit connecwith the foot. Indeed in all kinds of apparatus tions between the transmitting and receiving stait becomes possible to substitute a temporary aptions for the liquid and the present invention replication of force for a maintained one. lates to apparatus of this type. In some instances The following is a description, by way of exthe apparatus comprises two pistons and cylinders ample, of one distant control in accordance with at the transmitting station connected by two con- 2 the invention andof modifications thereof: duits to a corresponding pair of pistons and cyl- In the accompanying drawings: inders at the receiving station, but preferably in Figure 1 is a longitudinal section through a the use of the present invention there is only one transmitting station; piston and cylinder at each station and a single Figure 2 is a similar view of a receiving station; interconnecting pipe. Under the expression Figure 3 is a detail. piston-and-cylinder mechanism there is in- The apparatuscomprises the transmitting statended to be included such equivalents as bellows tion, Figure 1,- connected to a receivingstation, mechanism which, under the effect of hydraulic Figure 2, by means of a metal pipe I I. The transpressure, will produce movement of an actuated -mitting station consists of a cylinder l2 connected part to an extent proportional to the hydraulic .30 by a valve box I3 to the pipe II. The valve box flow. comprises an outer plate It which'carries a union According to the invention, in apparatus of the I5 for attachment to the pipe II; there is also kind described, valve means are provided at the an inner diaphragm H5 which is separated from transmitting station or the receiving station or the outer plate I4. by a space I6. In the diaboth which are-normally closed, but are autophragm H5 are two ports I I, I8. The port I! matically opened by movement at the transmitis closed by a lift valve I9 which is located in the ting station of the actuator so that the hydraulic space I6 and opens under the effect of pressure in liquid is locked against movement except un er the cylinder l2 against the action of alight spring the influence of the actuator-Q 20.

The apparatus may be'of the type inwhich a 40 In the cylinder I2 is a piston 2| and movement single piston and cylinder at the transmitting of the piston inwards in the cylinder I2, that is'to and receiving stations are interconnected by a' say in the direction towards the diaphragm H5, single pipe and return movements of the piston will open the lift valve II! but a return movement at the receiving station are effected by a yielding of the liquid from the pipe II into the cylinder I2 return member such as a spring orliquid under is not permitted by the valve I9. pressure. I The port I 8 is closed by a disc valve 22 which Preferably the valve means which close the rests on the cylinder side of the diaphragm H5 intercommunication conduit are such as to yield and opens inwardly into the cylinder. The disc under a predetermined pressure so that while the ak/e322 is closed y a sp g 23 of p ete ed actuated member resists stillly up to. a predeterstrength which bearson the back of the disc valve mined point, the application of force to it beyond this degree will permit it to yield.

' The invention may be applied to hydraulic control devices for all kinds-of purposes including,

for example, the brakes of vehicles, the distant control of parts on motor vehicles such as throttles and hydraulic jacks, the operation of a petrol gauge from a float, or the like; the invention may also be applied to all kinds of remote control deand is supported by a bracketllsecured to the diaphragm H5. Thus liquid cannot flow back from the pipe II into the cylinder l2 except through the disc valve 22, and such flow is prevented from occurring as long as the valve 22 is I moved inwardly to its greatest extent.

' force out hydraulic liq ui made sufllcient to hold the valve 22 closed against the efiect of such pressure in the pipe H as can be applied by the reaction against movements of the actuated member at the receiving station.

The disc valve 22 has secured to its cylinder a tubular stem which extends axially through the cylinder |2 and which enters and slides ina passage 2-6 extending through the centre of the piston 2|. The base part of the stem 25 is somewhat enlarged as shown at 21 and fits the walls of the passage 25 closely. The passage 26 i sufiiciently long to enable the piston 2|.to execute its full working stroke while still in contact with the enlarged end portion 21 of the valve stem 25. The

portion 21 joins the stem 25 with a shoulder as v shown at 28. An abutment plate 29 in the form of a washer is secured to the end-of the piston 2| so that the hole in the centre of the'abutment plate 29 surrounds the valve tem 25 closely.

The piston 2| is connected by a connecting rod 30 to a crank 3| and the crank has a spindle |3| which passes through one of the side walls32 which extend from the cylinder I2 upwardly on each side of the connecting rod 30. The. crank is provided with an actuating lever 33 so that the piston 2| can be moved up and down in the cylinder l2 to any extent desired. At one side of the cylinder l2 there is an oil reservoir chamber 35 andin the wall of the cylinder there is a port 35 which connects the reservoir chamber to the interior of the cylinder. The port 35 is located'in such a position that it is uncovered by the piston at the outer extremity of its stroke but is covered at all other times.

For reasons which will hereinafter appear the lever 33 on the crank 3| is made so as to be radially slidable through the hub of the crank and takes, the form of a rod having a handle 36 at one end and a cam roller 31 at the other. The cam roller works over a cam surface 38 secured to the interior of one of the side walls. The cam 38 is so shaped that as the lever 33 is moved angul'arly to operate the crank and to drive the piston 2| inwards, the lever slides through the hub of the crank 3| and the leverage of the lever over the hub is increased. Contact of the cam roller with the cam 38- during return movement is, ensured by a spring 39.

At the receiving station the mechanism comprises a cylinder fill containinga piston 5| which is connected by a connecting rod 62 to a crank 43 on a crankshaft M; the piston. 4| and cylinder 48 are made of similar dimensions to the piston 2| and cylinder |2 at the transmitting station, although these dimensions may be difierent if desired. The pipe II is connected to'an end cover 35 of the. cylinder 40. The crank 43 carries an arm 36 which constitutes an actuated member of the transmission and which may be coupled to any device which is to be operated, such, for

example, as an engine throttle, an aeroplane 40 where the liquid will cause the piston Al to moveoutwardly and operate the actuated member 46 to an extent which precisely corresponds to the extent of movement of the actuating lever 33. This movement is resisted by the spring 41 to an increasing extent as the stroke proceeds but the increasing force required to overcome the spring is balanced by the increased leverage of the handle 35 over the crank 3|. As oon as the movement of the lever 33 ceases, movement of the actuated member -46 ceases also. Any tendency of the actuated member 46 to return is prevented by the valves l8 and 22, for the valve l9 will remain shut against any return pressure, and'the valve 22 will be held closed by the spring 23; a relatively small force exerted by the sprin 23 can oppose a considerable force on the actuated member 56 because the area of the disc valve 22 is small in relation to the area of the piston 5 I.

When the actuated lever is moved in the return direction it will draw the piston 2| outwardly and produce suction in cylinder |2. Thi tends to lift valve 22. The pressure which is kept on the liquid in the pipe H by the spring 41 also tends to lift valve 22, and so does the dash-pot effect of liquid trapped between the shoulder 28 and abutment plate 29. The valve 22 will be lifted ofi' its rudder, a flap or other parts as mentioned herein-.5 I

before.

The piston 4| I is provided with a strong return spring '41 so that it tends always to return, against the action of any pressure in the hydraulic connections, to the position inwhich the piston is In the operation of this device. if the actuating lever 33iis moved'over at the transmitting station the piston 2| will be driven into the cylinder l2 to a corresponding degree. This will d through the valve .l'! and through the pipe into the cylinder seat by the combined effects of these three forces and the piston ll with the actuated member :15 will then be able to return. When the piston 2| reaches the outer end of its stroke it uncovers the port 35 and permits the liquid in the cylinder i2 to be replenished if any leak has occurred. Moreover the abutment disc 29'engages the shoulder on the stem 25 and ensures that the valve 22 is positively lifted oif its seat so that equalisation of pressure and synchronism of the actuator and the actuated member are automatically effected.

Referring now to Figure 3, this shows a modifled construction in which the cylinder |2 and piston 2| with their associated parts are similar to what has already been described except that the valve means connecting the cylinder i2 and the pipe I i are modified in the following respects: The valve 22 is replaced by a valve 50 having a long stem 5| which is' capable of sliding in the space 26 of the piston 2|. A long compression spring 62 which passe through the' space 25 tends to keep the valve 5|) on its seat. A clutch casing '53 is provided on the piston 2| around the stem 5| and contains a number of triangular clutch segment 53 which are pressed downwardly by a spring 55 and which rest upon an inclined conical face 55 in the bottom of the clutch casin 53. The clutch segments are therefore pressed by the spring 55 against the sides of the stem 5| and when the piston 2| is moved upwardly the clutch 50 is limited by a stop 51 engaging a bracket 58.

At any stage of the .outward movement a very slight return movement of the actuator 33 .will cause the valve 50 to seat and will lock the parts.

The use of the long spring 52 to hold the valve 50 on its seat ensures that the valve is held closed by a force which is increased the further the piston 2| is forced into-the cylinder l2. crease may be made to follow the same ratio as the increase in the return pressure of the spring in the receiving station. Thus the locking action of the valve 5| in preventing undesired re- This 111-:

turn movement of the actuated member at the receiving station will at all points of the stroke have the same excess value over the force exerted by th return spring 41 of the receiving station and the locking efiect will not vary at dif- Ierent points of the stroke.

Means may also be provided for compensatidg for the effects of variation of temperature. The

result of temperature variations is to lead to variations between the positions of the act tor and the actuated member. As the tempera ure increases a certain amount of'liquid is forced out of the intercommunication pipe into the re-,

ceiving cylinder and tends to move the actuated member accordingly.

I claim: 1. Hydraulic remote-control apparatus comprising a transmitter cylinder, a piston therein,

an actuator for said. piston, a receiver cylinder,

9. receiver piston therein, an actuated" member operatively connected to said receiver piston, a pipeline interconnecting the said two cylinders so that liquid in the pipeli e will cause motion of one piston to be comm 'cated to the other, a lift-valve opening under liquid flow from the transmitter to the receiver nd shutting against flow in a contrary directio a' second lift-valve in parallel with the first and shutting against liquid flow from the transmitter to the receiver,

a spring to hold said secondilift-valve closed against pressure exerted from he receiver up to a predetermined amount, as m on the said'secnd lift-valve and a friction evice on the transmitter piston in engagemeng with said stem to open-said second lift-valve: g'ainst said spring.

2. Hydraulic remote-control apparatus comprising a transmitter cylinder, a piston therein, an actuator for said piston, a receiver cylinder, 9. receiver piston therein, an actuated member operatively connected to said receiver piston, a

' pipeline interconnecting the said two cylinders so that liquid in the pipeline will cause motion of one piston to be communicated to the other, a lift-valve opening under liquid flow from the transmitter to the receiver and shutting against flow in a contrary direction, a second lift-valve in parallel withthe first and shutting against liquid flow from the transmitter to. the receiver,

3. Hydraulic remote-control apparatus com-.

prising a transmitter cylinder, a piston therein, an actuator for said piston, a receiver cylinder, a-receiver piston therein, an actuated member operatively connected to said receiver piston, a I

pipeline interconnecting the said two cylinders so that liquid in the pipeline will cause motion o f one piston to be communicated to the other, a lift-valve opening under, liquid flow from the transmitter to the receiver and shutting against flow in a contrary direction, a second lift-valve in parallel with the first and shutting against liquid flow from the transmitter to the receiver, a spring to hold said second lift-valve closed against pressure exerted from the receiver up to a predetermined amount, a dashpot device carried by the piston in the transmitter cylinder and means operatively connecting the dashpot.

device with the said second valve so as to open the valve whenever the piston moves outwardly relatively to the transmitter cylinder.

GEORGE AMERY. 

